Titanium Carbonitride Research Articles

The thermodynamic stability and mechanical properties of TiC x N1−x (0 ⩽ x ⩽ 1) compounds by cluster expansion method and first-principles calculations

The thermodynamic stability and mechanical properties of titanium carbonitrides TiC x N1−x (0 ⩽ x ⩽ 1) are investigated by a combination of the universal cluster expansion method and the first-principles calculations. By considering the ordering of the N/C distributions on the anion sublattice sites of TiC x N1−x , a binary diagram of the heat of formation is constructed, and seven kinds of ground-state structures are predicted in the whole range of 0 ⩽ x ⩽ 1. These predicted ground-state TiC x N1−x structures are further proved to be dynamically and mechanically stable by examining their phonon dispersion spectra and elastic constants. Further studies indicate that the mechanical and thermodynamic properties of the ternary TiC x N1−x structures are generally better than those of the binary TiC or TiN, while the differences within the ternary systems are insignificant. The possible origin of the enhancement of the mechanical and thermodynamic properties of the predicted ground-state TiC x N1−x are discussed together with the electronic structures.

Dispersion of Ni nanoparticles into Ti(C,N) colloidal filaments for 3D printing by FFF

Fabrication of dense inorganic parts using FFF requires the processing of a thermoplastic-based filament with a high content of inorganic particles, highly dispersed and an elevated final density. Titanium carbonitride base cermets are gaining interest as an alternative to cemented carbide W–Co. In this sense Ti(C, N)-based cermet have successfully densified by pressureless and vacuum sintering, demonstrating the suitability of Nickel (Ni) as binder phase. This work propose the preparation of filaments with high solid loadings of Ti(C, N), and the incorporation of Ni as nano-binder (nNi) to facilitate the final cermet sintering. With the control of the colloidal dispersion of Ti(C, N) and nNi, only a 3 ​vol% of nNi is needed to achieve the adequate sintering effect, providing the consolidated cermet structure with metallic conduction. The colloidal approach to FFF enhances the dispersion of the two inorganic phases within the polymer matrix, allowing high solid contents of the colloidal feedstock.

Effects of Activated Carbon Counter Electrode on Bifacial Dye Sensitized Solar Cells (DSSCs)

The losses of solar cells are consisted of electrical losses and optical losses. Optical losses chiefly reduce the short-circuit current. Here we apply bifacial cell approach to increase light absorption and the short-circuit current of dye sensitized solar cells (DSSCs). We have employed activated carbon (AC) as a very low cost counter electrode, an alternative to Pt counter electrode. Addition of dimethyl sulfoxide (DMSO) and titanium carbonitride (TiCN) to AC increase the efficiency of bifacial DSSC at a mirror angle of from 5.10% to and , respectively. These results indicate that AC has the potential to replace Pt as a very low cost counter electrode of bifacial DSSCs. The bifacial DSSC system using double plane mirrors improve PCE to for Pt counter electrode at a mirror angle of , and for AC counter electrode at a mirror angle of , respectively.

Effect of TiC, TiN, and TiCN on microstructural, mechanical and tribological properties of PM steels

Developments in sintering of powder mixtures contributed growth of steel production via powder metallurgy. This study aims to improve the mechanical and tribological properties of carbon steels produced via powder metallurgy. For this purpose, P/M carbon steel was alloyed with 3 % Manganese. Then, this alloyed steel was reinforced with particles such as titanium carbide (TiC), titanium nitride (TiN) and titanium carbonitride (TiCN) in different proportions (0.5 and 1 %) and combinations. The effect of these additives on the mechanical properties of PM steels was determined by conducting tensile and hardness tests. Wear tests were performed to understand the tribological properties of samples. Also, microstructural properties, fracture surfaces, and worn surfaces of samples were examined using a Scanning Electron Microscope. Results show that the hardness and tensile strength of carbon steel increased by nearly 158 % and 62 % respectively, while the wear resistance improved by 4 times with the addition of 3 % Mn and 0.5 % TiCN.

Підвищення властивостей деформованих алюмінієвих сплавів модифікованих нанокомпозиціями

The objective of the work is to obtain a dispersed structure and increase the mechanical and technological properties of deformed aluminum alloys by treating melts with nanodispersed modifiers. The effect of the modification by refractory nanodispersed compositions of titanium carbonitride and silicon carbide on the grain structure and properties of aluminum alloys has been established. Aluminum alloys of the Al-Mg, Al-Mg-Sc system have been studied. The scientific novelty of the work lies in the establishment of the mechanism of influence of the nanodispersed modifier on the grain structure and the set of properties of aluminum alloys. The composition of the modifier is proposed — nanodispersed powders of silicon carbide (SiC) and titanium carbonitride (TiCN) with fractions of 50 ... 100 nm. The microstructure of alloys was studied under optical microscopes. The strength properties of the alloys were determined on a TIRAtest300 machine. Fluidity was determined using the spiral test method. In the modified samples of aluminum alloys, improved technological properties were achieved. It was found that, in alloys AMg5 and 1545, the fluidity increased by an average of 10 %. After the modification, we obtained a homogeneous dispersed structure of aluminum alloys. It turned out that the average grain size in the modified samples of alloy 1545 decreased 1.6 times in comparison with the initial state due to the increase of strength characteristics by 14… 20 %. A series of experimental-industrial melting of AMg5 and 1545 alloys has been carried out. The effective influence of a refractory modifier based on silicon carbide and titanium carbonitride on the properties of aluminum alloys has been proved. The results of the work are of practical importance for aviation and space technology products.

Study of structure, phase composition and physicomechanical properties of modified castings from heat-temperature ZhS3DK alloy

A study of the structure and properties of castings made with the use of various modifiers has been carried out. It was found that when the alloys are modified with titanium carbonitride and all used modifiers except tungsten carbide, the grain size decreases, and carbide precipitates are evenly distributed, contributing to an increase in mechanical properties. Using the method of differential thermal analysis, the critical temperatures at which phase transformations occur in the cast ZhS3DK alloy and its analogs with modifiers have been established. The modes of heat treatment of modified cast heat-resistant alloys of the ZhS3DK type have been specified.

Synthesis and Properties of a Carbon Monoxide Oxidation Catalyst Based on Plasma-Chemical Titanium Carbonitride, Titanium Dioxide, and Palladium

A CO oxidation catalyst based on plasma-chemical titanium carbonitride TiC0.2N0.8 and TiO2 with a palladium content of 10 wt % has been synthesized. The dependence of the reaction rate of CO oxidation at room temperature and low CO concentrations (<100 mg/m3) on the TiC0.2N0.8 content has been studied. It has been found that, at TiC0.2N0.8 concentrations from 8 to 10 wt %, the catalyst exhibited a maximum rate of the CO oxidation reaction, which was 2.5 times higher than the rate of reaction on a catalyst based on pure TiO2 that included palladium clusters. The catalysts are promising for use in catalytic and photocatalytic systems for air purification.

Wear-Resistant TiCN-Based Ceramic Materials for High-Load Friction Units

The tribological properties of matrix and skeletal titanium carbonitride composites were studied in dry friction conditions in air. Experiments on wetting of the TiCN–Cr3C2 composite by nickel–chromium alloys and copper using the sessile drop method were performed to choose matrix composition and ascertain whether the samples could be produced by impregnation of the porous skeleton. The sessile drop experiments showed that nickel and its alloys formed a low contact angle on the TiCN–Cr3C2 composite (θ ≈ 8°). In particular, Ni3Al intermetallic had θ < 5°, allowing it to be used as a metal matrix. The same situation was observed for copper. A technique was developed for producing TiN–Cr3C2 composites by impregnation of the porous skeleton with Ni3Al and copper melts, and the tribological behavior of the cermets was tested in dry friction conditions. When the starting composite was impregnated with Ni3Al intermetallic, the friction coefficient decreased (μ = = 0.25). Structural studies were conducted with a MIM-10 metallographic microscope and X-ray diffraction with a DRON-2 diffractometer. The hardness and contact area thickness were measured employing a Falcon 9 hardness tester (manufactured in the Netherlands). Thin cross sections were made to examine the structure and phase composition of the contact area. The structure was analyzed using X-ray diffraction and scanning electron microscopy. The effect exerted by hardness of the counterface (steel 45, 40Kh, ShKh15) on the tribological properties of the TiCN–Cr3C2 composite was established. When steel hardness was 60 HRC, the friction coefficient increased with friction distance. These results were, however, obtained at low speeds and loads. Friction losses decreased with loading increasing from 2 to 6 MPa at 12 m/sec: friction coefficient reduced to 0.23. The TiCN–20% Cr3C2 cermets impregnated with Ni3Al may be recommended as antifriction materials for use in high-speed and high-load friction units.

Structure and properties of a tungsten-free hard alloy based on titanium carbonitride sintered from electroerosive powders obtained in a carbon-containing medium

The results of experimental studies of a KNT16 tungsten-free hard alloy sintered from electroerosive powders obtained in ethyl alcohol are presented. It is shown that the use of the spark plasma sintering method to produce products from powder obtained by electroerosive dispersion of the alloy KNT16 will ensure high performance of parts due to the uniformity of the surface, favorable structure and low porosity of the product.

Spark plasma sinterability and thermal diffusivity of TiN ceramics with graphene additive

The effects of adding graphene nano-platelets (6 wt%) on the microstructure and thermal diffusivity and conductivity of TiN-based ceramics were investigated. Two samples, a monolithic TiN, and a graphene-added TiN ceramics were fabricated using spark plasma sintering technique at 1900 °C for 7 min under 40 MPa. The microstructure of the polished and fractured surfaces of both samples was analyzed by scanning electron microscopy. Adding graphene resulted in a 2% reduction in the relative density, but led to obtaining a fine-grained microstructure. The consumption of graphene nano-additive during the sintering, through the reduction of surface oxide layers of TiN matrix (TiO2), and consequently, the formation of titanium carbonitride (TiN0·8C0.2) were disclosed by X-ray diffraction analysis. The measurement of the thermal diffusivity was done using the laser flash technique. The TiN–6 wt% graphene sample obtained lower thermal conductivity compared to the monolithic TiN, which can be attributed to the smaller grain size of the graphene-added sample.

Super-activated CNB for CO2 capture: The development of the nitrogen containing porous carbon by chlorination and post KOH-activation

Minimization of carbon dioxide (CO2) emissions into the atmosphere is a prerequisite to solving climate change. Tremendous research has been conducted to capture the CO2 from pre- and post-combustion using nanoporous materials. Nitrogen-doped porous carbon is one of the most promising CO2 adsorbents. Achieving high nitrogen content and high micropore volume is essential to CO2 adsorption properties. In this study, super activated nitrogen and boron co-doped porous carbons (K-CNBs) are successfully synthesized by the chlorination and the subsequent KOH chemical activation. Nitrogen and boron co-doped porous carbons (CNBs) are synthesized by the chlorination of titanium carbonitride and boride mixture. CNBs good thermal and oxidation stability that induces an increase in the nitrogen content as well as an increase in the micropore volume even after the activation. K-CNBs, having both high micropore volume and abundant pyridonic-N functional group, show superior CO2 uptake at ambient temperature at atmospheric pressure with excellent CO2/N2 selectivity. K-CNBs are the best CO2 capturer among the nitrogen-containing carbon materials, reaching the threshold of CO2 uptakes performance.

ИССЛЕДОВАНИЕ ПРОЧНОСТНЫХ СВОЙСТВ ПОКРЫТИЙ ИЗ КОМПОЗИЦИОННЫХ МАТЕРИАЛОВ С КВАЗИКРИСТАЛЛАМИ, ПОЛУЧЕННЫМИ МЕТОДОМ ГАЗОДИНАМИЧЕСКОГО НАПЫЛЕНИЯ

The work purpose is to investigate strength properties of composite coatings with quasi-crystals obtained through the method of gas dynamic sputtering. The object of development: quasi-crystals based on titanium carbonitride clad with nickel. In the course of the work there is offered a method for investigations of coating strength based on a pin and adhesive method with composites based on titanium carbonitride. The novelty of this investigation consists in obtaining new materials and investigations of their physical-mechanical properties. Composite coating on the basis of titanium carbonitride has shown high separation properties. The destruction took place in an intermediate layer between VN20 and KNTP35. During 10 mm bending there is a fine even mesh. At the impact load made there were not observed chips and separations that allow using coating data in heavy-loaded parts.

Investigation of irradiated metal of WWER-type reactor internals after 45 years of operation. Part 3. Microstructure and phase composition

TEM, SEM, and APT techniques have been used to analyze radiation-induced components of metal structure of fragments cut from the pressure vessel internals of Novovoronezh NPP Unit No 3 after 45 years of operation. The fragments differed in the neutron damaging doses (from 14 to 43 dpa) and the irradiation temperature (from 285 to 315°C). The density and dimensions of titanium carbides and carbonitrides, dislocation loops, radiation-induced voids, segregations, and nanoscale precipitates were determined. The contributions of structural components to the radiation hardening of the investigated fragments of 18Cr-10Ni-Ti stainless steel were estimated.

Tremella‐shaped TiCN Nanosheets as Anode mAterials of Lithium‐Ion Batteries

AbstractTransition metal carbides and nitrides have attracted more and more attention as excellent mAterials in the field of electrochemical energy storage. Here, we have taken a different approach to synthesize tremella‐like unique titanium carbonitride (TiCN) nanosheets by hydrothermal method and high temperature solid phase sintering. Through microscopic characterization, the final products are gathered together in the form of nanosheets or ribbons like individual petals, which creates mAny ion transports channels and voids. In addition, two different products were prepared by changing the basic conditions of the precursor. After comparing the microstructures of the two groups of products and their precursors, TiCN‐5 mol was mAinly studied. In terms of electrochemical performance, TiCN‐5 mol nanosheets possess higher reversible specific capacity (476mAhg−1 after 80 cycles) and excellent coulombic efficiency (98.5 % after 80 cycles) and superior rate performance up to 5000 mAg−1 (100 % of its capacity at 100 mAg−1 rate) compared to TiCN‐10 mol. The enhanced electrochemical performance is primarily due to the high specific surface area and low ion diffusion barrier of the TiCN nanosheets, which provides high ion electrical conductivity and plays an important role in reducing large volume expansion during prolonged cycling.

Evaluation of Sliding Wear Behaviour for STD11 Coated with TiCN Using the Pin-on-Disk Test

The forming process using ultra high strength steel (UHSS) may cause early damage than the expected lifetime of the tool surface due to the high reaction force of the material compared to the conventional steel sheet. This leads to the increase in the cost of maintenance of the tool and the decrease in the product productivity and quality. In this study, the sliding wear behavior of the titanium carbonitride (TiCN) physical vapor deposition (PVD) coated pin against UHSS was quantitatively evaluated from the pin-on-disk test based on the Taguchi method. S/N ratio and ANOVA are used to evaluate the sensitivity of process parameters affecting on the pin wear depth. Finally, a wear prediction model for the TiCN coated pin against UHSS was constructed by the power law equation.

Mineralogy and Microstructure of Skull Versions in AO EVRAZ NTMK Blast Furnace No. 6

Results of a comprehensive study of the material composition and microstructure of 20 skull samples taken after blowing out AO EVRAZ NTMK blast furnace No. 6 are provided. More than 30 mineral and metal phases of different chemical classes are diagnosed in skull samples. Unlike the skull of blast furnaces of other metallurgical plants (NLMK, ZSMK), NTMK blast furnace skull has an abnormally high content of titanium, zinc, and vanadium compounds, as well as heavy non-ferrous metals and sulfur. On the basis of detailed petrographic analysis, five structural and genetic types (versions of composition and origin) of the skull are identified. Skull versions contain a large amount of grenal, which is dominated by refractory compounds of titanium and vanadium carbonitrides of the general formula (Ti, V)(C, N).

Study on the High-temperature Properties of High-titania Slags produced with Cr-bearing Vanadia-titania Magnetite Smelting in Blast Furnace

The high-temperature metallurgical property of high-titania slag is one of the most significant indicators to measure the production status of Cr-bearing vanadia-titania magnetite blast furnace (CVTM-BF). Due to the continuous high temperature in the furnace, titania is over-reduced to titanium carbonitride with a high melting point (over 3000°C), which causes the viscosity of the slag to be too high to separate the molten iron and molten slag well. However, a high proportion of N2 in the air blasted into the furnace participates in the generation of TiN, and the large required air volume causes a high coke ratio and excessively high furnace temperature, which is not conducive to suppressing the over-reduction of titania. Here we show that TiN was significantly reduced and the metallurgical properties of high-titania slag were improved by injecting abandoned basic oxygen furnace gas (ABOFG), which is a kind of by-product gas containing CO, CO2, lower N2 and high physical heat. The experimental results demonstrated that the ABOFG was likely to function in suppressing TiN from 2.46% to 1.06%, dropping the melting temperature down from 1478.8°C to 1290.3°C, pushing the slag-iron interface tension from 0.641 N/m to 0.882 N/m as well as bring the viscosity down from 0.353 Pa⋅s to 0.341 Pa⋅s. Overall, ABOFG as a kind of endothermic atmosphere compared to O2-enriched air is beneficial to restrain the over-deduction of titania to TiN upon the slag-coke interface with lower N2. It also helps CVTM-BF to be recovered from the continued deterioration as soon as possible.

Mineralogy and microstructure of skull varieties in blast furnace № 6 JSC EVRAZ NTMK

The results of a comprehensive study of the material composition and microstructure of 20 skull samples taken after blowing out blast furnace № 6 of EVRAZ NTMK JSC are presented. More than 30 minerals and metal phases of different chemical classes were diagnosed in the samples of the skull. Unlike the skull of blast furnaces of other metallurgical plants (NLMK, ZSMK), the skull of NTMK blast furnaces has an abnormally high content of titanium, zinc, vanadium compounds, as well as heavy non-ferrous metals and sulfur. On the basis of a detailed petrographic analysis, 5 structural and genetic types (varieties in composition and origin) of the garnice were identified. The varieties of the garnish contain a large amount of grenal, which is dominated by refractory compounds of titanium and vanadium carbonitrides of the general formula (Ti, V) (C, N).

Material Science Aspects of Alloy Modification by Nanocompositions of Plasma-Chemical Synthesis

Crystallographic characteristics of nanodispersed materials obtained by plasma-chemical synthesis were studied. Using industrial equipment for plasma-chemical synthesis the nanodispersed powders of high-melting carbide, nitride, carbonitride and silicide class compounds based on titanium, magnesium, aluminium, silicon were obtained. Technology for synthesis of powder fraction less than 100 nm was developed. The efficiency of nanodisperce compositions use in smelting of structural steels was determined. In the result of 10Г2С steel modification with Ti (CN) nanopowder strength, plastic properties and impact toughness were improved. Elemental composition of nanodispersed composition was determined: SiC, TiC, TiN, Ti (CN), AlN, Mg2Si, Mg3N2. The elemental composition of synthesized compounds corresponded to stoichiometric composition. Microdiffractional patterns of the particles were analysed, it was shown that nanopowders belong to the solid crystalline bodies with metallic bond. It has been found, that titanium carbonitride Ti (CN) particles have face-centered and silicon carbide (SiC) particles have hexagonal crystal lattice. Experiments for steel 10Г2 and 10Г2С modifying with nanopowder compositions on base of Ti (CN) and SiC were carried out. The efficiency of nanodisperce compositions use in smelting of structural steels was determined. In the result of 10Г2С steel modification with Ti (CN) nanopowder strength, plastic properties and impact toughness were improved. The choice of nanodisperce titanium carbonitride Ti (CN) powders with 100 nm fraction for light alloy steels modifying was justified. The required criteria for choice of nanopowder modifiers were obtained: insolubility in smelt, correspondence of crystal lattice to steel matrix, commensurability with austenite germ critical radius in crystallizing.

Cobalt Nanoparticles Modified Single-Walled Titanium Carbonitride Nanotube Derived from Solid-Solid Separation for Oxygen Reduction Reaction in Alkaline Solution

Titanium carbonitrides have promising catalytic properties for oxygen reduction reaction (ORR). However, its synthesis normally requires high temperatures (1200–1800 °C), thus limiting research carried-out on them. The catalytic properties of the carbonitrides have so far been improved through post-synthesis partial surface oxidation. This makes the entire process of making the desired catalyst cumbersome and complex. In this work, cobalt-modified single-walled titanium carbonitride nanotube (Co@TiC0.25N0.75) is synthesized via solvothermal method followed by solid-solid separation process. The problem of high temperature required for TiCN synthesis is successfully overcome, and a Co doping strategy is used to improve its catalytic performance. Different mass ratios of Co nanoparticles are loaded onto TiC0.25N0.75. It discovers that only a fraction of the Co dissolves at TiC0.25N0.75 lattice due to the solubility limit being ~ 0.98%. The remaining fraction of Co is found at the wall of the TiC0.25N0.75. The Co nanoparticles at the TiC0.25N0.75 wall complement the catalytic activity, while the dissolved Co at its lattice acts as active site modifier by increasing the proportion of Ti 2p3/2 in the low valence state. In alkaline solution, 10%Co@TiC0.25N0.75 shows appreciable ORR activity with onset and half-wave potential located at 0.85 and 0.73 V respectively; the performance is higher than that of TiN (0.69 and 0.55 V) and single-phase TiC0.25N0.75 (0.74 and 0.62 V). The results indicate that a charge transfer occurred between Co and TiC0.25N0.75 due to strong coupling effect. This gives a catalyst with appreciable ORR activity and stability.